Off post privately owned firearms have been subject registration at various times and on different posts. Garrison Commanders or the Provost Marshals have promulgated local regulations to that effect.
I was at Fort Knox in 1986 when the Provost Marshal sent MPI out to local gun-shops to routinely "ask" to look at 4473's. FFL's were under no obligation to comply, but many did. No warrant is needed, if they "ask" and you say, "yes."
Currently, Fort Knox regulations state, in part:
http://www.knox.army.mil/garrison/dhr/asd/regs/r210-1.pdf a. The provisions of this regulation apply to all Department of Defense (DOD) active duty and retired military and civilian personnel; US Anny Reserve/National Guard (USAR/NG) personnel on post for active duty training or inactive training; military Family members; and civilians employed on, visiting, or traveling through w on the Fort Knox installation.
b. This regulation wilt not become void in its entirety merely because one part or portion thereof is declared unconstitutional or void.
c. This regulation is punitive. Military violators of regulations or this regulation may be prosecuted under the UCMJ or subject to administrative action. Civilian violators may be subject to administrative or judicial action under Title 18, United States Code (USC), or Assimilated Kentucky Revised Statutes.
And anyone who resides off-post who wishes to use MWR facilities to shoot, gets a card from the Morale, Welfare, Recreation office, after they fill out a a card recording all the pertinent information on the fire arm, and are run through a NICS check.
(1) DOD and nonmilitary affiliated civilians firing at an approved firing range for pleasure shooting must have a Morale, Welfare, and Recreation (MWR) card. This card will be obtained from the Directorate of Morale, Welfare, and Recreation (DMWR), and a National Crimes Information Center (NCIC) check will be conducted by DMWR before issuing any card. The NCIC check can be made by calling the military police (MPs) at 624-2443 or 5923. The card must be obtained before bringing any weapon on the installation and be retained on person at all times while on the installation. Individuals will also be required to sign in at French Range and present the MWR card when signing in. No one will be allowed to shoot without first obtaining the MWR card. Active duty, USARNG and retired military, and their Family members are not required to have an MWR card, but they must produce a military ID and sign in at French Range. Guests of a military ID or MWR cardholders are required to be signed in by the cardholder.
Prior to 2004, Fort Bragg required off-post personnel to register, see extract below, emphasis added.
http://www.bragg.army.mil/ProvostMarshal/FBRegs/FBReg190-12.docSUMMARY OF CHANGE
XVIII Airborne Corps & Fort Bragg Regulation 190-12
Privately Owned Weapons and Ammunition Control and Prohibited Weapons
This revision dated 1 December 2004
This is a comprehensive revision. The title has been changed from “Privately Owned Weapons and Ammunition Control and Prohibited Items,” to “Privately Owned Weapons and Ammunition Control and Prohibited Weapons,” to clarify the scope of the regulation. It outlines the requirements for purchasing, transporting, and storing privately owned weapons and ammunition on Fort Bragg (FB). It also lists prohibited weapons.
Eliminates the requirement for registering weapons brought on to Fort Bragg, but not actually stored on Fort Bragg. This includes situations like service members (SM) living off post (and storing their weapons off post), and unaffiliated personnel living off post who come on post only to hunt.
Fort Stewart, the registration form quietly omits any clarification between on and off-post requirements.
http://www.stewart.army.mil/des/documents/PrintableFSGAWeaponRegForm.pdfNow, maybe, just maybe, if I hadn't spent 26 years in the Army, you might be able to convince me that Commanders will not occasionally reach beyond what is legally permissible. Surely, no one has used a "Health and Welfare Inspection" as subterfuge for an illegal search! No one has take information on an MWR card to collect data they are not otherwise entitled to collect.